(a) Field of the Invention
The present invention provides an illumination beam shaping system, and more particularly provides an illumination beam shaping system which enables the emergent surface of a lighting system of light excitation chips to emit a light beam of uniform illumination brightness. The present invention produces a light beam from a point light source, such as an electrooptical light source, and a division operation is carried out at a position of the cross section of the light in the forward path of the light beam, whereby blocks of small areas of the projected cross section breadth of the light beam are divided and transformed into a plurality of juxtaposed conical light beams at different angular positions, and the bottom surface of each of the conical light beams distanced from the focal points thereof forms an actual optical surface. The actual optical surfaces act on an incident plane of an optical diffusing component, thereby enabling a system light emitting illuminating surface to emit a light beam of uniform illumination brightness.
(b) Description of the Prior Art
Lighting systems can be categorized according to the model type, including far-end projection, near-end illumination and substrate backlight and sign displays. Recently, LED (light-emitting diode) technology has reached maturity, and mainly because of the minute size and easy standardization of light emitting illumination angle of LEDs, thus, large quantities have been directed for use in forming directionable illumination applications, or secondary lighting for small spaces demanding low power, and already occupy a dominating position in illuminating apparatus. Moreover, the visual effects from the ability to modulate wave length and color temperature have been especially received. Although not able to completely replace traditional lamps provided with contextual aesthetic culture, however, its small size certainly has positive uses, being able to miniaturize the external form of illuminating apparatus, thus, related industries have vigorously dedicated use thereof in directional illumination equipment, including desk lamps or sign displays, such as display case lamps or even large outdoor lamps.
Because the size of an LED is very small, thus, its ability to produce power is limited by compression resistance of the material. Hence, a method whereby a cumulative number in a sequential or array arrangement is used to produce relatively high illumination lumen output, however, in a sequential or array assembled arrangement, because of the LED's innate tiny point illumination, thus, during operation, from the point of view of the light emitting illuminating surface, there exists a prominent difference when multiple intense distinctive luminescent points are compared with traditional lamps, especially the uniform illumination performance of fluorescent lamps. Moreover, illumination angle of each of the LEDs is a directional included angle conical illumination, which, particularly in a near-end desk lamp implementation, when acting on an illuminated surface, a block type spectrum with different degrees of light and shade illumination is formed on the surface, thus, the total emergent light must undergo equalization.
The uniform diffusion method adopted in the prior art is an implementation using Fresnel mirrors, perforated plates, or multiple reflection technologies, or scattering effect diffraction grating, all of which are able to carry out light beam shaping on light emitted from an LED light excitation chip to an appropriate degree. However, all the implementations greatly affect the rate of flow of light, resulting in loss in illumination lumen output. Hence, adopting a light beam shaping diffusion method can substantially eliminate lumen loss.
Designs for light beam shaping of the prior art (as depicted in FIG. 1) comprises a photoelectric component, a light excitation chip 101 able to produce light beams, and a separating optical member 102 provided with an optic axis, and a light beam output surface provided with a concave curved portion and a convex curved portion. At least part of the convex curved portion is distanced from the optic axis and encircles the concave curved portion. The optic axis passes through the concave curved portion, and the convex curved portion is provided with a first area and a second area. The degree of curvature of the first area is less than the degree of curvature of the second area, thereby enabling dispersion of the light beam emitted by the light source into different blocks of light energy within a widening angle range.
The Industrial Technology Research Institute of Taiwan have designed an optical diffusion module (as depicted in FIG. 2), comprising a first diffusion structure 103, provided with a plurality of first cylindrical lens and a plurality of second cylindrical lens, the first cylindrical lens and the second cylindrical lens are connected in a mutually continuous cross linking arrangement; a second diffusion structure 104, provided with a plurality of third cylindrical lens and a plurality of fourth cylindrical lens, connected in a mutually continuous cross linking arrangement, a light beam from the light source undergoes diffusion by passing through the first diffusion structure 103 and the second diffusion structure 104, and an additional fitted diffusion membrane 105 assists further diffusion of the emerging light. However, the shape of the light beam after cylindrical mirror refraction is a planar fan-shaped light beam perpendicular to the meridian plane, and because the lengthwise bodies of the cylindrical mirrors are distanced away from the light excitation chip, thus, it is subject to the square factor of the distance, and the refracted light energy close to the front and rear end positions is clearly less than that at the central point. Hence, regarding illumination beam distribution at the emergent face of the system, the lumen output of the refracted light at the center of the emergent face is correspondingly higher. As a consequence of the plurality of juxtaposed cylindrical mirrors, a light beam passing through the module from the light excitation chip results in an effect similar to a double slit interference effect, as proven by Young's slit interference experiments, in which, when an emergent light beam acts on the surface of an illuminated object, alternate stripes of light and shade appear, that is, there is a clear difference in light and shade, and thus does not achieve the objective of light uniformity. In addition, such technology completely adopts a diffusion construct, using the front and rear sets of diffusion structures to effect a two stage pre-diffusion operation, and, lastly, using a diffusion membrane 105 to further effect final diffusion. Furthermore, the first and second diffusion structures are respectively assembled from two sets of lenses, and different refraction curvatures are gradually apportioned to the front and rear breadths of the lenses. Apart from demanding high accuracy during manufacture, after assembling the numerous structural components, the diffusion system easily loses the desired shape, and requires perfect spacing. The aforementioned technology is applied in lamps provided with a cover surface, where shaping of the light beam is carried out for the emerging light, where diffusion effectiveness is finally resolved. However, because the working components are distanced away from the light source, thus, the light energy is already weakened due to the square factor of the distance. A change in directional refraction operation is then carried out, however, because the light energy is already substantially weakened, thus, the working effect is reduced, the reason for which is that because of the innate constraint of the refractive index of the refraction components.